#-*- coding: utf-8 -*-

# a與b都參照到immutable物件
a = b = 3
b = b + 1	# 重新指派b
print "a is: " + str( a )
print "b is: " + str( b )

print "\n====================================\n"

a = b = 0
b += 1	# 複合指派運算子，作用於immutable物件上，仍會重新指派
print "a is: " + str( a )
print "b is: " + str( b )

print "\n====================================\n"

a = b = 20
b + 5	# 沒有重新指派
print "a is: " + str( a )
print "b is: " + str( b )

print "\n====================================\n"

a = b = 20
c = b + 5	# 把運算式結果指派給c
print "a is: " + str( a )
print "b is: " + str( b )
print "c is: " + str( c )